Comparison of Sodium, Potassium, Hemoglobin, and Glucose Levels by Blood Gas Analyzer and Hospital Laboratory...

In emergency department (ED) settings, accurate and timely measurement of biochemical parameters like sodium, potassium, hemoglobin (Hb), and glucose is critical for initiating appropriate interventions. These parameters can be measured by a hospital laboratory autoanalyzer (HLA) or a blood gas analyzer (BGA). Although BGAs, as compared to HLAs, are able to deliver rapid results at the point of care, their accuracy has been a subject of debate. Therefore, this study was designed to compare them and determine their interchangeability.

A prospective, cross-sectional study was conducted in 1,000 adult patients in the Emergency Medicine Department. Both arterial sampling for blood gas analysis and venous sampling for laboratory analysis were taken simultaneously. The reliability between two measurements was evaluated using the intraclass correlation coefficient (ICC), and agreement was assessed using Bland-Altman analysis with 95% limits of agreement (LOA).

The intraclass correlation coefficient indicated good to excellent reliability for all parameters: Sodium (ICC = 0.946, 95% CI: 0.790-0.976), potassium (ICC = 0.907, 95% CI: 0.769-0.951), Hb (ICC = 0.947, 95% CI: 0.938-0.953), and glucose (ICC = 0.967, 95% CI: 0.962-0.971). The Bland-Altman plot showed moderate to high agreement for sodium, potassium, and Hb levels, and the mean bias was within acceptable limits. Despite the excellent ICC and high correlation for glucose, the Bland-Altman analysis revealed a substantial bias (+6.19 mg/dL) and very wide LOA (-67.69 to +80.07 mg/dL), indicating poor agreement.

We advocate the use of BGA for sodium, potassium, and Hb measurement in emergency settings for quick decision-making. However, glucose measurements from BGA require careful interpretation and should be supplemented with laboratory testing.

Mittal G, Gupta K, Kaushal A, Chauhan R, Sharma N, Singh K, et al. Comparison of Sodium, Potassium, Hemoglobin, and Glucose Levels by Blood Gas Analyzer and Hospital Laboratory Autoanalyzer in Emergency Department Settings: A Cross-sectional Study. Indian J Crit Care Med 2025;29(12):1020-1025.